The present invention relates to an image projector or image forming method for projecting a light beam onto the object to form a visible image on the object.
In a prior art image projector as disclosed in JP-A-9-230499, a two-dimensional visible image is formed on an optically transparent plate including crystalline liquid, and the visible image is projected onto a screen by passing a light beam through the optically transparent plate toward the screen.
As a deflector for changing or deflecting a light beam proceeding direction, a galvano mirror as disclosed in JP-A-7-218857 is know publicly.
An object of the present invention is to provide an image projector or image forming method for forming a visible image on an object, in which image projector or image forming method a number of light sources is significantly small, a two-dimensional visible image need not to be formed, and a large size and/or high resolution of the visible image on the object is obtained.
According to the present invention, an image projector for forming a visible image on an object, comprises, a light beam projector for projecting a light beam, and a deflector for changing frequently a proceeding direction in which the projected light beam proceeds to change a position of a surface area on the object which surface area is to be irradiated by the projected light beam so that the irradiated surface area is moved rapidly and repeatedly over the object to form the visible image on the object.
Since the proceeding direction is changed frequently to change the position of the surface area on the object which surface area is to be irradiated by the projected light beam so that the irradiated surface area is moved rapidly and repeatedly over the object to form the visible image on the object, a number of light sources for forming the visible image is significantly small, and a two-dimensional visible image need not to be formed before being projected onto the object while a large size and/or high resolution of the visible image on the object is obtained.
If the light beam includes at least two element light beams for respectively irradiating simultaneously the surface areas apart from each other, a frequency of the rapid and repeated movement of the irradiated surface area on the object is decreased. The element light beams may be arranged along an imaginary substantially straight line as seen in the proceeding direction in the light beam projector so that the light beam is long-and-narrow shaped as seen in the proceeding direction to irradiate simultaneously the surface areas apart from each other along the imaginary substantially straight line on the object as seen in the proceeding direction. If the surface areas along the imaginary substantially straight line are repeatedly moved on the object in a direction substantially perpendicular to the imaginary substantially straight line as seen in the proceeding direction so that the visible image is kept on the object, a band-shape of the visible image is formed rapidly on the object. If the surface areas along the imaginary substantially straight line are repeatedly shiftable on the object in a direction substantially parallel to the imaginary substantially straight line as seen in the proceeding direction so that the visible image is kept on the object, an elongated shape of the visible image is formed rapidly on the object. The element light beams along the imaginary substantially straight line may arranged exactly on the imaginary substantially straight line as seen in the proceeding direction or may be staggered relative to the imaginary substantially straight line as seen in the proceeding direction.
At least one of color and luminous intensity of the light of beam or at least one of the element light beams may changed in accordance with the movement of the surface area on the object, so that complex picture elements are formed in the visible image on the object.
The light beam projector comprises at least two light sources for generating respective color component light beams different from each other in color to be combined into the light beam or at least one of the element light beams, so that complexed colorful picture elements are formed in the visible image on the object.
If the light beam projector comprises a light source for generating the light beam, and an optical fiber connected to the light source to transmit the light beam from the light source toward the deflector, a positional relationship between the light source and the deflector may be freely set desirably by utilizing a flexibility of the optical fiber. If the light beam projector comprises at least two light sources for generating respective color component light beams different from each other in color to be combined into the light beam, and an optical fiber connected to each of the light sources to transmit the color component light beam from each of the light sources toward the deflector, a positional relationship between each of the light sources and the deflector may be freely set desirably by utilizing a flexibility of the optical fiber.
If the surface areas along the imaginary substantially straight line are moved on the object in a direction substantially perpendicular to the imaginary substantially straight line on the object as seen in the proceeding direction, and subsequently, the surface areas along the imaginary substantially straight line are moved again on the object in the direction substantially perpendicular to the imaginary substantially straight line on the object as seen in the proceeding direction after the surface areas along the imaginary substantially straight line are moved on the object in a direction substantially parallel to the imaginary substantially straight line on the object as seen in the proceeding direction, so that the visible image is formed by stacking sequentially in the direction substantially parallel to the imaginary substantially straight line the visible image formed by the simultaneously irradiated surface areas along the imaginary substantially straight line moved rapidly in the direction substantially perpendicular to the imaginary substantially straight line, the visible image of large size and high resolution is obtained on the object without a large number of light sources and a two-dimensional visible image formed before projected onto the object.
The light beam may include an incoherent light beam. The light beam projector may comprise at least one of organic electro-luminescent element and light emitting diode for generating the light beam.
The deflector may include a rotatable mirror arranged to receive the light beam so that the proceeding direction is changed frequently. The rotatable mirror may be rotatable continuously in a rotational direction on an rotational axis or swingable in directions opposite to each other to reciprocate circumferentially. The rotatable mirror may include a plurality of rotatable element mirrors arranged distributively around the rotational axis to receive respectively the light beam.
If the light beam is prevented from being projected toward the object when the surface areas along the imaginary substantially straight line is shifted relatively largely on the object in a direction substantially parallel to the imaginary substantially straight line on the object as seen in the proceeding direction, and the light beam is projected toward the object when the positions of the surface areas along the imaginary substantially straight line are kept substantially constant (including shifted slightly) on the object in the direction substantially parallel to the imaginary substantially straight line on the object as seen in the proceeding direction, a clearness of the visible image on the object is maintained or is prevented from being deteriorated by an interference between the irradiated and shifted surface areas along the imaginary substantially straight line. If the light beam is projected toward the object when the positions of the surface areas along the imaginary substantially straight line are kept substantially constant (including shifted slightly) on the object in the direction substantially parallel to the imaginary substantially straight line on the object as seen in the proceeding direction while the positions of the surface areas along the imaginary substantially straight line are changed on the object in a direction substantially perpendicular to the imaginary substantially straight line on the object as seen in the proceeding direction, a clearness of each of the picture elements formed by the surface areas along the imaginary substantially straight line is kept without the interference between the irradiated and shifted surface areas along the imaginary substantially straight line.
If the light beam is prevented from being projected toward the object when the rotatable mirror is swung in one of the directions opposite to each other, and the light beam is projected toward the object when the rotatable mirror is swung in another one of the directions opposite to each other, a control for energizing the light beam projector and/or driving the deflector is simplified to keep the clearness of the visible image.
If the light beam is prevented from being projected toward the object when the proceeding direction is directed toward a boundary or corner between the element mirrors circumferentially adjacent to each other, the visible image is prevented from being deteriorated by the light beam reflected irregularly by the boundary or corner between the element mirrors.
If the surface area is shiftable on the object in directions opposite to each other or substantially perpendicular to each other, the light beam is projected toward the object when the surface area is shifted on the object in one of the directions, and the light beam is prevented from being projected toward the object when the surface area is shifted on the object in another one of the directions, a control for energizing the light beam projector and/or driving the deflector is simplified.
It is preferable that the element light beams proceed substantially parallel to each other between the light beam projector and the deflector or when the element light beams are received by the deflector. It is preferable that the element light beams simultaneously proceeding from the deflector toward the object are substantially parallel to each other.
If the light beam or at least one of the element light beams is projected from the light beam projector toward the deflector after the color component light beams different from each other in color are mixed with each other to form or be combined into the light beam or the at least one of the element light beams, a relative displacement between color components in each of the picture elements is prevented so that a color is even over the whole of the each of the picture elements.